Particle size and shape

If the particle size distribution of a system is changed by comminution processes, the particles almost always have a different shape from the sphere.  If you look at a real particle, a particle size of this one particle can be given in a variety of ways. In a sieve analysis, the particle is compared to a screen mesh size. This can be square, rectangular or round. The result, however, is more or less a tendon length.

In many cases, image analysis measurement methods work with the projection surface as a measurand, while sedimentation analyses or surface measuring instruments always start from the spherical shape of the particles when calculating the particle size distribution.

Depending on the measurement method, the particle size is therefore given as results that correspond to a shere equivalent value (e.g. sphere of the same surface, sphere of the same sinking velocity or sphere of the same volume).

It is therefore always important to understand how the analysis method used works and what error influences exist.